SSCC E-mail and Linux Server Outage Saturday Evening

SSCC email and Linux interactive servers (Hal, Kite, and Falcon) will be unavailable this Saturday evening from 10:00 p.m. to 2:00 a.m. so that we can move everyone's email to a new upgraded server. During the downtime you will not be able to read or send email, and incoming email will be stored for later delivery.  Hal, Kite, and Falcon will not be accepting logins and all three servers will be rebooted at some point (removing any jobs that were started before the downtime). The Condor server will be available (and not rebooted), as will SSCC-hosted web pages except for SquirrelMail.

Spam - Where has it all gone?

Using a new mail server purchased with Capital Exercise funds, we were able to upgrade our spam filtering software called SpamAssassin and also implement a new program called policyd-weight. Together these two programs have done a phenominal job in keeping spam out of our Inboxes.

The policyd-weight program runs various network tests on an email message and the server the message came from before the message is even accepted by our server. If it fails the tests, it will reject the message outright. These tests only take about a second per message. During our three months of testing, this program would have rejected about 80,000 messages a day.

We've needed to upgrade SpamAssassin for quite a while but the program's more extensive and effective rules significantly degrades email performance. The idea behind using policyd-weight and SpamAssassin at the same time is that SpamAssassin only has to deal with a fraction of the email it did before, so its slower performance is less of an issue.

The only problems we've encountered since the programs' implementation is a couple of cases where our mail server bounced back messages because the remote mail server was mis-configured. (Misconfigured mail servers are usually zombie servers sending out spam.) If a message you send (from your ISP) is unexpectedly bounced or a message someone sends you gets bounced back, just let us know and we will add the mail server's address to our "white list" so that it doesn't happen again.

New Interactive Linux Servers

SSCC's interactive Linux servers, Hal, Kite and Falcon, have been replaced. All three now have two Quad Core Intel Xeon processors (for a total of eight physical processors) running at 3.0GHz. Hal and Kite now have 10GB of RAM, and Falcon has 14GB. In our testing, the new servers completed computational tasks in 1/2 to 2/3 the time the old servers required.

Kite and Hal are the SSCC's primary Linux servers. Both have a variety of statistical software installed, including Stata/MP, SAS and R. They also have the usual Linux utilities and compilers. Kite and Hal both run 32-bit Linux and have the same 3 gigabyte per job limit as Winstat, but they usually get much closer to that limit. Stata/MP can claim about 2.8 gigabytes of memory on Hal and Kite. Kite and Hal are much better than Winstat for computationally-intensive jobs. Stata/MP is the multiprocessor version of Stata, which means it will use two processors to run a single job. This makes it much faster than the standard Stata installed on Winstat.

Falcon is a 64-bit Linux server for jobs that require more memory than 32-bit operating systems can provide, or programs that require 64-bit Linux. Installed software includes Stata/MP, R and SPSS. Falcon has the same CPUs as Hal and Kite (two 3.0GHz Quad Core Intel Xeon processors) and will not run most jobs any faster than they will. However it has 14 gigabytes of RAM and can use temp space on disk as virtual memory if needed. Stata jobs can claim nearly 29 gigabytes of memory on Falcon. Falcon should be reserved for jobs that cannot be run anywhere else.

For more information about using Kite and Hal, see Connecting to SSCC Linux Computers and/or the SSCC Linux Handbook.

Change to Procedures for New SSCC Accounts

As physical location becomes less and less relevant to computing in general and SSCC services in particular, it's become more of a challenge to make sure that new SSCC members get a basic understanding of how their account works. As a result we will now require that all new accounts be "activated" using a tool on our web site (in the past activation has been optional). This involves two changes:

  1. New accounts must be requested online. We will no longer use paper forms.
  2. New SSCC members will not be given a starting password. Instead they'll get a unique activation code which they'll use to start the activation process. The activation process includes choosing the password they'll use to log in to SSCC services.

The account activation process is very brief, and includes basics like choosing a password, setting security questions and reading SSCC email. We feel strongly that all new members will benefit from going through this process. It is also more secure than simply sending new members a starting password.

Note that this does not apply to SOE accounts. SOE members who wish to use SSCC services should speak with their local SOE tech support contact in order to have their SOE account set up for the SSCC.

In-building Training Opportunity on Campus's Calendaring Program WiscCal

DoIT staff will be presenting an overview of the campus's calendaring program called WiscCal on July 23rd, 9:00-10:30 in Social Science 3218. WiscCal is designed to help view, schedule and modify meetings, manage resources, tasks, and other entries on the UW-Madison campus. Participants in the training session will learn how to get started using WiscCal and have the opportunity to ask questions related to implementing the calendaring program in campus departments. Visit SSCC's training web page to register.

Reminder: Never Save Files on your Windows Desktop when Using Winstat

When you're using Winstat, it's very important that you save the files you create on network drives, like U:, X:, H: or P:. These locations are secure and backed up nightly. Never save files on your Windows Desktop or in My Documents.

The Windows Desktop and My Documents are part of your Windows profile. Files saved there are not backed up and can be lost if your session crashes or gets disconnected. We cannot emphasize enough how important it is to log off (Start: Log Off) of Winstat rather than disconnecting by closing the window. If you just close the window the ICA client is running in, your profile is not saved. When files on the Desktop or in My Documents are lost it's usually related to disconnected sessions.